similar to: Change class of elements in list

Hi, I have a matrix of data which i can vizualize as an image - for example. I would like to save this image as a geotiff file or at a tiff file with a world file which holds the projection of my data (ultimately the data represent a map of some sort). I know i can save the data as an ESRI grid, but i am not interested in that. I wonder if anybody knows about any code which will help me do

Hello list I am trying to use a Googlemaps tile (png file, 640 X 640 px tile) as a background to a plot and have been using the rgdal library to read in the PNG file (modified from code in the RGoogleMaps package). This works OK. My problem is is that the SGDF2PCT function in rgdal seems to be limited to 256 colors and this is introducing (I think) some degradation to the image which appears on

R-geographers... I'm trying to solve a problem to implement a line-by-line tiled processing using RGDAL (read 1 line of an image, process the one line, write one line of the image to a binary file). Everything except for the final step I'm able to do using a combination of RGDAL and r-base commands. Below is the basic structure, the input file "elev" can be any image file

Hi, Doing more search i've discovered package RGDAL that can write a geotiff file with projection. I saved a geotiff file in UTM projection and if i read the file back in R and check the projection seems that everything is OK. But if i load the file in ArcGIS (ESRI product) i get the warning that the file is missing spatial reference so it cannot be projected, but it is displayed correctly.

Dear all, Several days ago, I posted How to write a bmp file pixel by pixel. Instead of bmp, I succeeded in writing a PPM file by using the pixmap package. Thanks for the hint generously provided by Uwe Ligges. Now I have a new question. How to convert a PPM file to BMP file in R? I know I can do this in photoshop or by some other softwares, but I think if I Can do this in R, that

Hi, I am very new to R and I am trying to write KML files. I am running R-2.13.1 and I have the following packages: - AKIMA - RGDAL - RSAGA - SP I was trying to run the simple example that I found at the following web page: http://spatial-analyst.net/wiki/index.php?title=Export_maps_to_GE The lines that I can run are: data(meuse.grid)

I can define a list containing NULL elements: > myList <- list("aaa",NULL,TRUE) > names(myList) <- c("first","second","third") > myList $first [1] "aaa" $second NULL $third [1] TRUE > length(myList) [1] 3 However, if I assign NULL to any of the list element then such element is deleted from the list: > myList$second <-

Hello: I would like to superimpose vector polygons (state outlines) from a Shape file on top of a satellite image, imported into a SpatialGridDataFrame from GEOTIFF via gdal_translate and readGDAL. When I plot polygon and point shape files in R, into SpatialPointDataFrame and SpatialPolygonDataFrame, the two feature sets line up geographically, so it seems logical that a SpatialGridDataFrame

I have a list that is made of lists of varying length. I wish to create a new vector that contains the last element of each list. So far I have used sapply to determine the length of each list, but I'm stymied at the part where I index the list to make a new vector containing only the last item of each list mylist =

Hi! I have a list of 24 elements, all of the same type (dataframe, for example). I am looking for an alternative to mylist[[1]] + mylist[[2]] + ... + mylist[[24]] to obtain the sum. Anyone can help me? Thanks in advance. Nicola S. [[alternative HTML version deleted]]

Hello! # I have a list with several data frames: mylist<-list(data.frame(a=1:2,b=2:3), data.frame(a=3:4,b=5:6),data.frame(a=7:8,b=9:10)) (mylist) # I want to grab only one specific column from each list element neededcolumns<-c(1,2,0) # number of the column I need from each element of the list # Below, I am doing it using a loop: newlist<-NULL for(i in 1:length(mylist) ) {

Hi everybody, I have a list, where every element of this list is a data frame. An example: Mylist<-list(A=data.frame, B=data.frame, C=data.frame, D=data.frame) I want to rbind some elements of this list. As an example: Output<-list(AB=data.frame, CD=data.frame) Where AB=rbind(A,B) CD=rbind(C,D) I’ve tried: f<-function(x){ for (i in

Dear listers, I have a collection of tif images that I would like to convert, in R, to a matrix containing the values of the 8bit colour. Ideally, I would like a matrix for each of the colour channels (red, blue and green). I have 'googled' and searched the help list but have yet to find a solution and hope that someone can point me in the right direction. I currently use

Hi   I have a problem for saving grid file in R. I want to save a grid file as "tif".   I write this: writeGDAL(predict.grid, 'predict.tif')   after running, I don't recieve any error. But when I want to open the 'file.tif', it doesn't open. for example in paint program: I recieve this: Paint cannot read this file. This is not valid bitmap file, or its format

Hi guys, here is a simple thing I want to do but it doesn't work: I have a vector of the element indexes that I want to delete called index so when I write myList[[index]] <- NULL to delete these elements here is what I get: Error in myList[[index]] <- NULL : more elements supplied than there are to replace Isn't it possible to delete multiple elements? ----- Anna Lippel --

Hello I tried to define replacement functions for the class "mylist". When I test them in an active R session, they work -- however, when I put them into a package, they don't. Why and how to fix? make_my_list <- function( x, y ) { return(structure(list(x, y, class="mylist"))) } mylist <- make_my_list(1:4, letters[3:7]) mylist mylist[['x']] <- 4:6

Hi, I'm pretty new to R. I have an object (say a list) and I I have a function that I call on various columns in that list (excuse terminology if it's wrong/ambiguous). Imagine its like this (actual values are unimportant) and called mylist: >mylist A B 1 5 2 5 3 6 4 8 5 0 I have a function: foo = function(param){ #modify list A or B values depending on

Hi, I'm have a list of integer vectors and I want to perform an outer() like operation on the list. As an example, take the following list: mylist <- list(1:5,3:9,8:12) A simple example of the kind of thing I want to do is to find the sum of the shared numbers between each vector to give a result like: result <- array(c(15,12,0,12,42,17,0,17,50), dim=c(3,3)) Two for() loops is the

Dear R users, Let's say I have a list with components being 'm' matrices (as exemplified in the "mylist" object below). Now, I'd like to subset this list based on an index vector, which will partition each matrix 'm' in 2 sub-matrices. My questions are: 1. Is there an elegant way to have the results shown in mylist2 for an arbitrary number of matrices in mylist?

Hi I have a list : mylist <- list( a = NULL, b = 1, c = 2 ) > mylist[1] $a NULL > is.null(mylist[1]) [1] FALSE > is.null(mylist$a) [1] TRUE why? I need to use mylist[1]